A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE. 



" To the solid ground 

 Of Nature trusts the mind which builds for aye." — Wordsworth. 



No. 2574. Vol. 102 1 THURSDAY, FEBRUARY 27, 1919 



[Price Ninepence. 



Registered as n NcwspsiiM-r rii the Oenenil Post Office ] 



[All Rights Reserved 



OPTICAL LANTERNS 



for 



Educational, Welfare, Scientific, and other 

 WORK of NATIONAL IMPORTANCE 



NEWTON <st CO., 



Makers of Optical Projection Apparatus of every description 



(Establish™ ovek »» Years). 



72 WIGMORE STREET, LONDON. W. 1. 



DUROGLASS L™ 



14 CROSS STREET, HATTON GARDEN, E.C. 



Manufacturers of 



Borosilicatc Resistance Glassware. 



Beakers. Flasks, Etc. 

 Soft Soda Tubing for Lamp Work. 



General Chemical and 



Scientific Glassware. 



Special Glass Jlpparatus Made to Order. 



DUROGLASS WORKS, WALTHAMSTOW. 



AGENTS: 



BAIRD & TATLOCK (LONDON) LTD. 

 14 CROSS ST., HATTON GARDEN, E.C.I. 



CHEMICALS 



Analytical, Technical and Research. 



RECO. TRADE MARK APPARATUS 



Balances 



BENCHES 



Fume Chambers, etc., 

 for 



a snow crystal Chemical Laboratories 

 Price Lists and Estimates on Application. 



REYNOLDS & BRANSON, LTD., 



Contractors to the War Office, Admiralty, and 

 Egyptian Government, &c. , 



14 COMMERCIAL STREET, LEEDS. 



BECKMANN THERMOMETERS 



With 6 degrees Centigrade divided 

 into 001° C, are now made 

 throughout at our own works. 



NEGRETTI & ZAMBRA 



38 HOLBORN VIADUCT, E.C. 1 

 5 LEADENHALL ST., E.C. 3 

 122 REGENT STREET, W. 1 



LONDON. 



